Drying calcium hypochlorite compounds



UNITED STATES V 1572,95: PATENT OFFICE.

I GUSTAV PISTOB, F GRIESHEIM-ON-THE-MAIN, GERMANY, ASSIGNOB TOGHEIIIQGHE FABRIK GBIESHEIM-ELEKTRON, OF FRANKFORT-ON-THE-IAIN, GERMANY:

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Ho Drawing.

To all whom it may concern: Be it known that I, GUST-AV PIs'roR, acitizen of Germany, residing at GIIGShGlIIl-Oll ",the Main, Germany,have invented certain pochlorite.

present invention.

new and useful Improvements in Drying Calcium Hypochlorite Compounds,

of which the following is a specification.

This invention relates to improvements in the drying of calciumhypochlorite compounds, especially by means of hygroscopic salts, oxidesand the like. It is well-known that the stability of the neutral orbasic calcium hypochlorite compounds .practically free from chloride isa matter of greatest importance with a view to their practical use.Hitherto calcium hypochlorite was carefully dried in vacuo or in acurrent of hot air, as it had been found that even very small quantitiesof moisture considerably accelerate the decomposition of calcium hy-However it is diflicult in many respects to remove even these lastremnants of moisture by means of heat with or without the aid of avacuum.

Now I have found that a complete drying of calcium hypochlorite may beattained v far more rapidly and in a far more economic manner thathitherto by following the combined method forming the object of the Thiscombined method consists in a preliminary drying of the calciumhypochlorite by means of heat to a small percentage of moisture, say 1per cent, and then removing the remainder of'water by the addition ofhygroscopic media. Such substances are for instance any hygroscopicsalts and oxides, sofar as these substances are not able to chemicallyreact with calcium hypochlorite under mutual decomposition, such asquicklime (CaO) or calcined gypsum.

This simple method results in increasing the stability of the productsthus obtained as compared with'that of the products dried by heat alone.

It is a known fact that hygroscopic salts, oxides and the like areemployed for removing moisture, especially the addition of caustic limeto' bleaching powder is well known. However in this case largequantities of quicklime, at least 30 per cent must be added in order towholly combine with lime the water present, whereby only a very lowgradeproduct is obtained. In contradis- Application filed March 26, 1925.Serial No. 18,828.

tinction to this with my improved method the addition of hygroscopicsubstances may be so small that the percentage of active "chlorine inthe product obtained is not cons'id'erably diminished, as in con'eque'nce of prior drying all the water, e remnants, has ben removed fromthe product which originally contained but little water.

Furthermore I have found it advantageous to introduce the additionduring the last stage of the drying product is still hot, where thewater contents are rapidly and entirely transferred to the additionalsubstance. K. I

It may be understoodthat in connection with the method forming theobject of my present invention the terms calcium hypochlorite or calcium.hypochlorite compounds comprise as well the neutral calciumhypochlorite as its basic combinations.

1. The method of drying calcium hypochlorite compounds, narily dryin thesaid compoundsby treating them wit 1 heat to a small percentage of waterand then mixing them with. hygroscopic substances which are incapable ofreacting with calcium hypochlorite under mutual decomposition. p

2. The method of drying calcium hypochlorite compounds, consisting inpreliminarily drying the said compoundsby treating them with heat invacuo to a small percentage of water and then mixing-them withhygroscopic substances which are incapable of reacting with calciumhypochlorite under mutual decomposition.

3. The method of drying calcium hypochlorite compounds, consisting inpreliminarily drying the said compounds by,treating them with heat to asmall percentage of water' and then mixing them While hot withhygroscopic substances.

4. The method of drying calcium hypochlorite compounds, consisting inpreliminarily drying the said compounds by treating them with heat invacuo to a small percentage of water and then mixing them while hot withhygroscopic substances.

5. The method of drying calcium hypochlorite compounds, consisting inpreliminarily drying the said compounds by treating them with heat to asmall percentage of cept slight rocess, while the v fyater and thenmixing them with quick- 6. The method of drying calcium h pochloritecompounds, consisting in pre iminarily drying the said compounds bytreating them with heat in vacuo to a small percentage of water and thenmixing them with quicklime.

7. The method of drying calcium hypochlorite compounds, consisting inpreliminaril drying the said compounds by treating t em with heat to asmall percentage of water and then mixing them while hot with quicklime.

8. The method of drying calcium h pochlorite compounds, consisting inpre iminarily drying the said compounds by treating them with heat invacuo to a small percentage of water and then mixing them while hot withquicklime.

In testimony whereof I afiix my signature.

GUSTAV PISTOR.

